MotoGP title leader Jorge Lorenzo set pace during a sunny Thursday morning practice session for the Dutch TT at Assen.
The Factory Yamaha star moved ahead of title rival and long time session leader Casey Stoner with two-minutes of the session remaining, with Stoner losing a further place to Repsol Honda team-mate Dani Pedrosa by the chequered flag.
But lap times were incredibly close at the top, with the top three covered by 0.075s.
Lorenzo starts round seven with a 25-point advantage over Stoner. Lorenzo (4) and Stoner (2) are the only riders to win races so far this year
Ben Spies, who took his only MotoGP victory to date in dominant fashion at Assen last year, finished the session in fourth place, 0.449s from team-mate Lorenzo.
Fellow American and fellow Assen winner Nicky Hayden was the top Ducati rider in sixth (+0.735s) with Silverstone pole sitter Alvaro Bautista completing the top six for Honda Gresini (+0.761s).
Pramac Ducati's Hector Barbera, Yamaha Tech 3 team-mates Andrea Dovizioso and Cal Crutchlow, then Ducati's Valentino Rossi completed a top ten covered by 0.978s.
Rookie Stefan Bradl was over half-a-second from Rossi after is first Assen RCV session, with Aspar Aprilia team-mates Randy de Puniet (+2.0s) and Aleix Espargaro (+2.2s) once again leading the CRT challenge.
Cardion AB Ducati's Karel Abraham made his return to action with 15th place out of the 21 riders, after missing the British MotoGP due to finger fractures in his left hand sustained in testing at Aragon.
The Assen circuit is the only survivor from the inaugural 1949 World Championship calendar. The Dutch TT is traditionally held on the last Saturday in June, Sunday racing having originally been frowned upon for religious reasons.
Second practice takes place this afternoon.
Thursday practice (1):
1. Jorge Lorenzo
2. Dani Pedrosa
3. Casey Stoner
4. Ben Spies
5. Nicky Hayden
6. Alvaro Bautista
7. Hector Barbera
8. Andrea Dovizioso
9. Cal Crutchlow
10. Valentino Rossi
11. Stefan Bradl
12. Randy De Puniet
13. Aleix Espargaro
14. Michele Pirro
15. Karel Abraham
16. Mattia Pasini
17. Yonny Hernandez
18. Colin Edwards
19. Danilo Petrucci
20. James Ellison
21. Ivan Silva